How often is she sneezing?
Any mucous from the nostrils or water/bubbly/pus filled eyes?
How long have you had her?
If you have vet care or can get some testing to find out more about the cause of her symptoms that's best.
There are several respiratory diseases that can look similar - some are bacterial while others are viral. Antbiotics can help treat symptoms of bacteria like diseases like Mycoplasma and Infectious Coryza. Viral diseases like Infectious Bronchitis usually run their course over a period of weeks, but sometimes antibiotics are needed as supportive care to treat secondary infection.
If it's Mycoplasma, then the Oxymav B (Oxytetracycline) can be used to treat symptoms. Some use Tylosin or Tiamulin.
Keep in mind respiratory diseases make birds carriers and antibiotics are not a cure, but used to treat/control infection and act as supportive care.
Environmental causes of respiratory symptoms should also be looked at as well - mold/mildew, poor ventilation and ammonia are a few.
Here's more information about respiratory diseases
http://edis.ifas.ufl.edu/ps044